<?php
// {{{ license

/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4 foldmethod=marker: */
//
// +----------------------------------------------------------------------+
// | This library is free software; you can redistribute it and/or modify |
// | it under the terms of the GNU Lesser General Public License as	   |
// | published by the Free Software Foundation; either version 2.1 of the |
// | License, or (at your option) any later version.					  |
// |																	  |
// | This library is distributed in the hope that it will be useful, but  |
// | WITHOUT ANY WARRANTY; without even the implied warranty of		   |
// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU	|
// | Lesser General Public License for more details.					  |
// |																	  |
// | You should have received a copy of the GNU Lesser General Public	 |
// | License along with this library; if not, write to the Free Software  |
// | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 |
// | USA.																 |
// +----------------------------------------------------------------------+
//

// }}}

/**
 * Encode/decode Internationalized Domain Names.
 *
 * The class allows to convert internationalized domain names
 * (see RFC 3490 for details) as they can be used with various registries worldwide
 * to be translated between their original (localized) form and their encoded form
 * as it will be used in the DNS (Domain Name System).
 *
 * The class provides two public methods, encode() and decode(), which do exactly
 * what you would expect them to do. You are allowed to use complete domain names,
 * simple strings and complete email addresses as well. That means, that you might
 * use any of the following notations:
 *
 * - www.nörgler.com
 * - xn--nrgler-wxa
 * - xn--brse-5qa.xn--knrz-1ra.info
 *
 * Unicode input might be given as either UTF-8 string, UCS-4 string or UCS-4
 * array. Unicode output is available in the same formats.
 * You can select your preferred format via {@link set_paramter()}.
 *
 * ACE input and output is always expected to be ASCII.
 *
 * @author  Matthias Sommerfeld <mso@phlylabs.de>
 * @copyright 2004-2007 phlyLabs Berlin, http://phlylabs.de
 * @version 0.5.1
 *
 */
class idna_convert
{
	/**
	 * Holds all relevant mapping tables, loaded from a seperate file on construct
	 * See RFC3454 for details
	 *
	 * @var array
	 * @access private
	 */
	var $NP = array();

	// Internal settings, do not mess with them
	var $_punycode_prefix = 'xn--';
	var $_invalid_ucs =	 0x80000000;
	var $_max_ucs =		 0x10FFFF;
	var $_base =			36;
	var $_tmin =			1;
	var $_tmax =			26;
	var $_skew =			38;
	var $_damp =			700;
	var $_initial_bias =	72;
	var $_initial_n =	   0x80;
	var $_sbase =		   0xAC00;
	var $_lbase =		   0x1100;
	var $_vbase =		   0x1161;
	var $_tbase =		   0x11A7;
	var $_lcount =		  19;
	var $_vcount =		  21;
	var $_tcount =		  28;
	var $_ncount =		  588;   // _vcount * _tcount
	var $_scount =		  11172; // _lcount * _tcount * _vcount
	var $_error =		   false;

	// See {@link set_paramter()} for details of how to change the following
	// settings from within your script / application
	var $_api_encoding   =  'utf8'; // Default input charset is UTF-8
	var $_allow_overlong =  false;  // Overlong UTF-8 encodings are forbidden
	var $_strict_mode	=  false;  // Behave strict or not

	// The constructor
	function idna_convert($options = false)
	{
		$this->slast = $this->_sbase + $this->_lcount * $this->_vcount * $this->_tcount;
		if (function_exists('file_get_contents')) {
			$this->NP = unserialize(file_get_contents(dirname(__FILE__).'/npdata.ser'));
		} else {
			$this->NP = unserialize(join('', file(dirname(__FILE__).'/npdata.ser')));
		}
		// If parameters are given, pass these to the respective method
		if (is_array($options)) {
			return $this->set_parameter($options);
		}
		return true;
	}

	/**
	 * Sets a new option value. Available options and values:
	 * [encoding - Use either UTF-8, UCS4 as array or UCS4 as string as input ('utf8' for UTF-8,
	 *		 'ucs4_string' and 'ucs4_array' respectively for UCS4); The output is always UTF-8]
	 * [overlong - Unicode does not allow unnecessarily long encodings of chars,
	 *			 to allow this, set this parameter to true, else to false;
	 *			 default is false.]
	 * [strict - true: strict mode, good for registration purposes - Causes errors
	 *		   on failures; false: loose mode, ideal for "wildlife" applications
	 *		   by silently ignoring errors and returning the original input instead
	 *
	 * @param	mixed	 Parameter to set (string: single parameter; array of Parameter => Value pairs)
	 * @param	string	Value to use (if parameter 1 is a string)
	 * @return   boolean   true on success, false otherwise
	 * @access   public
	 */
	function set_parameter($option, $value = false)
	{
		if (!is_array($option)) {
			$option = array($option => $value);
		}
		foreach ($option as $k => $v) {
			switch ($k) {
			case 'encoding':
				switch ($v) {
				case 'utf8':
				case 'ucs4_string':
				case 'ucs4_array':
					$this->_api_encoding = $v;
					break;
				default:
					$this->_error('Set Parameter: Unknown parameter '.$v.' for option '.$k);
					return false;
				}
				break;
			case 'overlong':
				$this->_allow_overlong = ($v) ? true : false;
				break;
			case 'strict':
				$this->_strict_mode = ($v) ? true : false;
				break;
			default:
				$this->_error('Set Parameter: Unknown option '.$k);
				return false;
			}
		}
		return true;
	}

	/**
	 * Decode a given ACE domain name
	 * @param	string   Domain name (ACE string)
	 * [@param	string   Desired output encoding, see {@link set_parameter}]
	 * @return   string   Decoded Domain name (UTF-8 or UCS-4)
	 * @access   public
	 */
	function decode($input, $one_time_encoding = false)
	{
		// Optionally set
		if ($one_time_encoding) {
			switch ($one_time_encoding) {
			case 'utf8':
			case 'ucs4_string':
			case 'ucs4_array':
				break;
			default:
				$this->_error('Unknown encoding '.$one_time_encoding);
				return false;
			}
		}
		// Make sure to drop any newline characters around
		$input = trim($input);

		// Negotiate input and try to determine, whether it is a plain string,
		// an email address or something like a complete URL
		if (strpos($input, '@')) { // Maybe it is an email address
			// No no in strict mode
			if ($this->_strict_mode) {
				$this->_error('Only simple domain name parts can be handled in strict mode');
				return false;
			}
			list ($email_pref, $input) = explode('@', $input, 2);
			$arr = explode('.', $input);
			foreach ($arr as $k => $v) {
				if (preg_match('!^'.preg_quote($this->_punycode_prefix, '!').'!', $v)) {
					$conv = $this->_decode($v);
					if ($conv) $arr[$k] = $conv;
				}
			}
			$input = join('.', $arr);
			$arr = explode('.', $email_pref);
			foreach ($arr as $k => $v) {
				if (preg_match('!^'.preg_quote($this->_punycode_prefix, '!').'!', $v)) {
					$conv = $this->_decode($v);
					if ($conv) $arr[$k] = $conv;
				}
			}
			$email_pref = join('.', $arr);
			$return = $email_pref . '@' . $input;
		} elseif (preg_match('![:\./]!', $input)) { // Or a complete domain name (with or without paths / parameters)
			// No no in strict mode
			if ($this->_strict_mode) {
				$this->_error('Only simple domain name parts can be handled in strict mode');
				return false;
			}
			$parsed = parse_url($input);
			if (isset($parsed['host'])) {
				$arr = explode('.', $parsed['host']);
				foreach ($arr as $k => $v) {
					$conv = $this->_decode($v);
					if ($conv) $arr[$k] = $conv;
				}
				$parsed['host'] = join('.', $arr);
				$return =
						(empty($parsed['scheme']) ? '' : $parsed['scheme'].(strtolower($parsed['scheme']) == 'mailto' ? ':' : '://'))
						.(empty($parsed['user']) ? '' : $parsed['user'].(empty($parsed['pass']) ? '' : ':'.$parsed['pass']).'@')
						.$parsed['host']
						.(empty($parsed['port']) ? '' : ':'.$parsed['port'])
						.(empty($parsed['path']) ? '' : $parsed['path'])
						.(empty($parsed['query']) ? '' : '?'.$parsed['query'])
						.(empty($parsed['fragment']) ? '' : '#'.$parsed['fragment']);
			} else { // parse_url seems to have failed, try without it
				$arr = explode('.', $input);
				foreach ($arr as $k => $v) {
					$conv = $this->_decode($v);
					$arr[$k] = ($conv) ? $conv : $v;
				}
				$return = join('.', $arr);
			}
		} else { // Otherwise we consider it being a pure domain name string
			$return = $this->_decode($input);
			if (!$return) $return = $input;
		}
		// The output is UTF-8 by default, other output formats need conversion here
		// If one time encoding is given, use this, else the objects property
		switch (($one_time_encoding) ? $one_time_encoding : $this->_api_encoding) {
		case 'utf8':
			return $return;
			break;
		case 'ucs4_string':
		   return $this->_ucs4_to_ucs4_string($this->_utf8_to_ucs4($return));
		   break;
		case 'ucs4_array':
			return $this->_utf8_to_ucs4($return);
			break;
		default:
			$this->_error('Unsupported output format');
			return false;
		}
	}

	/**
	 * Encode a given UTF-8 domain name
	 * @param	string   Domain name (UTF-8 or UCS-4)
	 * [@param	string   Desired input encoding, see {@link set_parameter}]
	 * @return   string   Encoded Domain name (ACE string)
	 * @access   public
	 */
	function encode($decoded, $one_time_encoding = false)
	{
		// Forcing conversion of input to UCS4 array
		// If one time encoding is given, use this, else the objects property
		switch ($one_time_encoding ? $one_time_encoding : $this->_api_encoding) {
		case 'utf8':
			$decoded = $this->_utf8_to_ucs4($decoded);
			break;
		case 'ucs4_string':
		   $decoded = $this->_ucs4_string_to_ucs4($decoded);
		case 'ucs4_array':
		   break;
		default:
			$this->_error('Unsupported input format: '.($one_time_encoding ? $one_time_encoding : $this->_api_encoding));
			return false;
		}

		// No input, no output, what else did you expect?
		if (empty($decoded)) return '';

		// Anchors for iteration
		$last_begin = 0;
		// Output string
		$output = '';
		foreach ($decoded as $k => $v) {
			// Make sure to use just the plain dot
			switch($v) {
			case 0x3002:
			case 0xFF0E:
			case 0xFF61:
				$decoded[$k] = 0x2E;
				// Right, no break here, the above are converted to dots anyway
			// Stumbling across an anchoring character
			case 0x2E:
			case 0x2F:
			case 0x3A:
			case 0x3F:
			case 0x40:
				// Neither email addresses nor URLs allowed in strict mode
				if ($this->_strict_mode) {
				   $this->_error('Neither email addresses nor URLs are allowed in strict mode.');
				   return false;
				} else {
					// Skip first char
					if ($k) {
						$encoded = '';
						$encoded = $this->_encode(array_slice($decoded, $last_begin, (($k)-$last_begin)));
						if ($encoded) {
							$output .= $encoded;
						} else {
							$output .= $this->_ucs4_to_utf8(array_slice($decoded, $last_begin, (($k)-$last_begin)));
						}
						$output .= chr($decoded[$k]);
					}
					$last_begin = $k + 1;
				}
			}
		}
		// Catch the rest of the string
		if ($last_begin) {
			$inp_len = sizeof($decoded);
			$encoded = '';
			$encoded = $this->_encode(array_slice($decoded, $last_begin, (($inp_len)-$last_begin)));
			if ($encoded) {
				$output .= $encoded;
			} else {
				$output .= $this->_ucs4_to_utf8(array_slice($decoded, $last_begin, (($inp_len)-$last_begin)));
			}
			return $output;
		} else {
			if ($output = $this->_encode($decoded)) {
				return $output;
			} else {
				return $this->_ucs4_to_utf8($decoded);
			}
		}
	}

	/**
	 * Use this method to get the last error ocurred
	 * @param	void
	 * @return   string   The last error, that occured
	 * @access   public
	 */
	function get_last_error()
	{
		return $this->_error;
	}

	/**
	 * The actual decoding algorithm
	 * @access   private
	 */
	function _decode($encoded)
	{
		// We do need to find the Punycode prefix
		if (!preg_match('!^'.preg_quote($this->_punycode_prefix, '!').'!', $encoded)) {
			$this->_error('This is not a punycode string');
			return false;
		}
		$encode_test = preg_replace('!^'.preg_quote($this->_punycode_prefix, '!').'!', '', $encoded);
		// If nothing left after removing the prefix, it is hopeless
		if (!$encode_test) {
			$this->_error('The given encoded string was empty');
			return false;
		}
		// Find last occurence of the delimiter
		$delim_pos = strrpos($encoded, '-');
		if ($delim_pos > strlen($this->_punycode_prefix)) {
			for ($k = strlen($this->_punycode_prefix); $k < $delim_pos; ++$k) {
				$decoded[] = ord($encoded{$k});
			}
		} else {
			$decoded = array();
		}
		$deco_len = count($decoded);
		$enco_len = strlen($encoded);

		// Wandering through the strings; init
		$is_first = true;
		$bias	 = $this->_initial_bias;
		$idx	  = 0;
		$char	 = $this->_initial_n;

		for ($enco_idx = ($delim_pos) ? ($delim_pos + 1) : 0; $enco_idx < $enco_len; ++$deco_len) {
			for ($old_idx = $idx, $w = 1, $k = $this->_base; 1 ; $k += $this->_base) {
				$digit = $this->_decode_digit($encoded{$enco_idx++});
				$idx += $digit * $w;
				$t = ($k <= $bias) ? $this->_tmin :
						(($k >= $bias + $this->_tmax) ? $this->_tmax : ($k - $bias));
				if ($digit < $t) break;
				$w = (int) ($w * ($this->_base - $t));
			}
			$bias = $this->_adapt($idx - $old_idx, $deco_len + 1, $is_first);
			$is_first = false;
			$char += (int) ($idx / ($deco_len + 1));
			$idx %= ($deco_len + 1);
			if ($deco_len > 0) {
				// Make room for the decoded char
				for ($i = $deco_len; $i > $idx; $i--) {
					$decoded[$i] = $decoded[($i - 1)];
				}
			}
			$decoded[$idx++] = $char;
		}
		return $this->_ucs4_to_utf8($decoded);
	}

	/**
	 * The actual encoding algorithm
	 * @access   private
	 */
	function _encode($decoded)
	{
		// We cannot encode a domain name containing the Punycode prefix
		$extract = strlen($this->_punycode_prefix);
		$check_pref = $this->_utf8_to_ucs4($this->_punycode_prefix);
		$check_deco = array_slice($decoded, 0, $extract);

		if ($check_pref == $check_deco) {
			$this->_error('This is already a punycode string');
			return false;
		}
		// We will not try to encode strings consisting of basic code points only
		$encodable = false;
		foreach ($decoded as $k => $v) {
			if ($v > 0x7a) {
				$encodable = true;
				break;
			}
		}
		if (!$encodable) {
			$this->_error('The given string does not contain encodable chars');
			return false;
		}

		// Do NAMEPREP
		$decoded = $this->_nameprep($decoded);
		if (!$decoded || !is_array($decoded)) return false; // NAMEPREP failed

		$deco_len  = count($decoded);
		if (!$deco_len) return false; // Empty array

		$codecount = 0; // How many chars have been consumed

		$encoded = '';
		// Copy all basic code points to output
		for ($i = 0; $i < $deco_len; ++$i) {
			$test = $decoded[$i];
			// Will match [-0-9a-zA-Z]
			if ((0x2F < $test && $test < 0x40) || (0x40 < $test && $test < 0x5B)
					|| (0x60 < $test && $test <= 0x7B) || (0x2D == $test)) {
				$encoded .= chr($decoded[$i]);
				$codecount++;
			}
		}
		if ($codecount == $deco_len) return $encoded; // All codepoints were basic ones

		// Start with the prefix; copy it to output
		$encoded = $this->_punycode_prefix.$encoded;

		// If we have basic code points in output, add an hyphen to the end
		if ($codecount) $encoded .= '-';

		// Now find and encode all non-basic code points
		$is_first  = true;
		$cur_code  = $this->_initial_n;
		$bias	  = $this->_initial_bias;
		$delta	 = 0;
		while ($codecount < $deco_len) {
			// Find the smallest code point >= the current code point and
			// remember the last ouccrence of it in the input
			for ($i = 0, $next_code = $this->_max_ucs; $i < $deco_len; $i++) {
				if ($decoded[$i] >= $cur_code && $decoded[$i] <= $next_code) {
					$next_code = $decoded[$i];
				}
			}

			$delta += ($next_code - $cur_code) * ($codecount + 1);
			$cur_code = $next_code;

			// Scan input again and encode all characters whose code point is $cur_code
			for ($i = 0; $i < $deco_len; $i++) {
				if ($decoded[$i] < $cur_code) {
					$delta++;
				} elseif ($decoded[$i] == $cur_code) {
					for ($q = $delta, $k = $this->_base; 1; $k += $this->_base) {
						$t = ($k <= $bias) ? $this->_tmin :
								(($k >= $bias + $this->_tmax) ? $this->_tmax : $k - $bias);
						if ($q < $t) break;
						$encoded .= $this->_encode_digit(intval($t + (($q - $t) % ($this->_base - $t)))); //v0.4.5 Changed from ceil() to intval()
						$q = (int) (($q - $t) / ($this->_base - $t));
					}
					$encoded .= $this->_encode_digit($q);
					$bias = $this->_adapt($delta, $codecount+1, $is_first);
					$codecount++;
					$delta = 0;
					$is_first = false;
				}
			}
			$delta++;
			$cur_code++;
		}
		return $encoded;
	}

	/**
	 * Adapt the bias according to the current code point and position
	 * @access   private
	 */
	function _adapt($delta, $npoints, $is_first)
	{
		$delta = intval($is_first ? ($delta / $this->_damp) : ($delta / 2));
		$delta += intval($delta / $npoints);
		for ($k = 0; $delta > (($this->_base - $this->_tmin) * $this->_tmax) / 2; $k += $this->_base) {
			$delta = intval($delta / ($this->_base - $this->_tmin));
		}
		return intval($k + ($this->_base - $this->_tmin + 1) * $delta / ($delta + $this->_skew));
	}

	/**
	 * Encoding a certain digit
	 * @access   private
	 */
	function _encode_digit($d)
	{
		return chr($d + 22 + 75 * ($d < 26));
	}

	/**
	 * Decode a certain digit
	 * @access   private
	 */
	function _decode_digit($cp)
	{
		$cp = ord($cp);
		return ($cp - 48 < 10) ? $cp - 22 : (($cp - 65 < 26) ? $cp - 65 : (($cp - 97 < 26) ? $cp - 97 : $this->_base));
	}

	/**
	 * Internal error handling method
	 * @access   private
	 */
	function _error($error = '')
	{
		$this->_error = $error;
	}

	/**
	 * Do Nameprep according to RFC3491 and RFC3454
	 * @param	array	Unicode Characters
	 * @return   string   Unicode Characters, Nameprep'd
	 * @access   private
	 */
	function _nameprep($input)
	{
		$output = array();
		$error = false;
		//
		// Mapping
		// Walking through the input array, performing the required steps on each of
		// the input chars and putting the result into the output array
		// While mapping required chars we apply the cannonical ordering
		foreach ($input as $v) {
			// Map to nothing == skip that code point
			if (in_array($v, $this->NP['map_nothing'])) continue;

			// Try to find prohibited input
			if (in_array($v, $this->NP['prohibit']) || in_array($v, $this->NP['general_prohibited'])) {
				$this->_error('NAMEPREP: Prohibited input U+'.sprintf('%08X', $v));
				return false;
			}
			foreach ($this->NP['prohibit_ranges'] as $range) {
				if ($range[0] <= $v && $v <= $range[1]) {
					$this->_error('NAMEPREP: Prohibited input U+'.sprintf('%08X', $v));
					return false;
				}
			}
			//
			// Hangul syllable decomposition
			if (0xAC00 <= $v && $v <= 0xD7AF) {
				foreach ($this->_hangul_decompose($v) as $out) {
					$output[] = (int) $out;
				}
			// There's a decomposition mapping for that code point
			} elseif (isset($this->NP['replacemaps'][$v])) {
				foreach ($this->_apply_cannonical_ordering($this->NP['replacemaps'][$v]) as $out) {
					$output[] = (int) $out;
				}
			} else {
				$output[] = (int) $v;
			}
		}
		// Before applying any Combining, try to rearrange any Hangul syllables
		$output = $this->_hangul_compose($output);
		//
		// Combine code points
		//
		$last_class   = 0;
		$last_starter = 0;
		$out_len	  = count($output);
		for ($i = 0; $i < $out_len; ++$i) {
			$class = $this->_get_combining_class($output[$i]);
			if ((!$last_class || $last_class > $class) && $class) {
				// Try to match
				$seq_len = $i - $last_starter;
				$out = $this->_combine(array_slice($output, $last_starter, $seq_len));
				// On match: Replace the last starter with the composed character and remove
				// the now redundant non-starter(s)
				if ($out) {
					$output[$last_starter] = $out;
					if (count($out) != $seq_len) {
						for ($j = $i+1; $j < $out_len; ++$j) {
							$output[$j-1] = $output[$j];
						}
						unset($output[$out_len]);
					}
					// Rewind the for loop by one, since there can be more possible compositions
					$i--;
					$out_len--;
					$last_class = ($i == $last_starter) ? 0 : $this->_get_combining_class($output[$i-1]);
					continue;
				}
			}
			// The current class is 0
			if (!$class) $last_starter = $i;
			$last_class = $class;
		}
		return $output;
	}

	/**
	 * Decomposes a Hangul syllable
	 * (see http://www.unicode.org/unicode/reports/tr15/#Hangul
	 * @param	integer  32bit UCS4 code point
	 * @return   array	Either Hangul Syllable decomposed or original 32bit value as one value array
	 * @access   private
	 */
	function _hangul_decompose($char)
	{
		$sindex = (int) $char - $this->_sbase;
		if ($sindex < 0 || $sindex >= $this->_scount) {
			return array($char);
		}
		$result = array();
		$result[] = (int) $this->_lbase + $sindex / $this->_ncount;
		$result[] = (int) $this->_vbase + ($sindex % $this->_ncount) / $this->_tcount;
		$T = intval($this->_tbase + $sindex % $this->_tcount);
		if ($T != $this->_tbase) $result[] = $T;
		return $result;
	}
	/**
	 * Ccomposes a Hangul syllable
	 * (see http://www.unicode.org/unicode/reports/tr15/#Hangul
	 * @param	array	Decomposed UCS4 sequence
	 * @return   array	UCS4 sequence with syllables composed
	 * @access   private
	 */
	function _hangul_compose($input)
	{
		$inp_len = count($input);
		if (!$inp_len) return array();
		$result = array();
		$last = (int) $input[0];
		$result[] = $last; // copy first char from input to output

		for ($i = 1; $i < $inp_len; ++$i) {
			$char = (int) $input[$i];
			$sindex = $last - $this->_sbase;
			$lindex = $last - $this->_lbase;
			$vindex = $char - $this->_vbase;
			$tindex = $char - $this->_tbase;
			// Find out, whether two current characters are LV and T
			if (0 <= $sindex && $sindex < $this->_scount && ($sindex % $this->_tcount == 0)
					&& 0 <= $tindex && $tindex <= $this->_tcount) {
				// create syllable of form LVT
				$last += $tindex;
				$result[(count($result) - 1)] = $last; // reset last
				continue; // discard char
			}
			// Find out, whether two current characters form L and V
			if (0 <= $lindex && $lindex < $this->_lcount && 0 <= $vindex && $vindex < $this->_vcount) {
				// create syllable of form LV
				$last = (int) $this->_sbase + ($lindex * $this->_vcount + $vindex) * $this->_tcount;
				$result[(count($result) - 1)] = $last; // reset last
				continue; // discard char
			}
			// if neither case was true, just add the character
			$last = $char;
			$result[] = $char;
		}
		return $result;
	}

	/**
	 * Returns the combining class of a certain wide char
	 * @param	integer	Wide char to check (32bit integer)
	 * @return   integer	Combining class if found, else 0
	 * @access   private
	 */
	function _get_combining_class($char)
	{
		return isset($this->NP['norm_combcls'][$char]) ? $this->NP['norm_combcls'][$char] : 0;
	}

	/**
	 * Apllies the cannonical ordering of a decomposed UCS4 sequence
	 * @param	array	  Decomposed UCS4 sequence
	 * @return   array	  Ordered USC4 sequence
	 * @access   private
	 */
	function _apply_cannonical_ordering($input)
	{
		$swap = true;
		$size = count($input);
		while ($swap) {
			$swap = false;
			$last = $this->_get_combining_class(intval($input[0]));
			for ($i = 0; $i < $size-1; ++$i) {
				$next = $this->_get_combining_class(intval($input[$i+1]));
				if ($next != 0 && $last > $next) {
					// Move item leftward until it fits
					for ($j = $i + 1; $j > 0; --$j) {
						if ($this->_get_combining_class(intval($input[$j-1])) <= $next) break;
						$t = intval($input[$j]);
						$input[$j] = intval($input[$j-1]);
						$input[$j-1] = $t;
						$swap = true;
					}
					// Reentering the loop looking at the old character again
					$next = $last;
				}
				$last = $next;
			}
		}
		return $input;
	}

	/**
	 * Do composition of a sequence of starter and non-starter
	 * @param	array	  UCS4 Decomposed sequence
	 * @return   array	  Ordered USC4 sequence
	 * @access   private
	 */
	function _combine($input)
	{
		$inp_len = count($input);
		foreach ($this->NP['replacemaps'] as $np_src => $np_target) {
			if ($np_target[0] != $input[0]) continue;
			if (count($np_target) != $inp_len) continue;
			$hit = false;
			foreach ($input as $k2 => $v2) {
				if ($v2 == $np_target[$k2]) {
					$hit = true;
				} else {
					$hit = false;
					break;
				}
			}
			if ($hit) return $np_src;
		}
		return false;
	}

	/**
	 * This converts an UTF-8 encoded string to its UCS-4 representation
	 * By talking about UCS-4 "strings" we mean arrays of 32bit integers representing
	 * each of the "chars". This is due to PHP not being able to handle strings with
	 * bit depth different from 8. This apllies to the reverse method _ucs4_to_utf8(), too.
	 * The following UTF-8 encodings are supported:
	 * bytes bits  representation
	 * 1		7  0xxxxxxx
	 * 2	   11  110xxxxx 10xxxxxx
	 * 3	   16  1110xxxx 10xxxxxx 10xxxxxx
	 * 4	   21  11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
	 * 5	   26  111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
	 * 6	   31  1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
	 * Each x represents a bit that can be used to store character data.
	 * The five and six byte sequences are part of Annex D of ISO/IEC 10646-1:2000
	 * @access   private
	 */
	function _utf8_to_ucs4($input)
	{
		$output = array();
		$out_len = 0;
		$inp_len = strlen($input);
		$mode = 'next';
		$test = 'none';
		for ($k = 0; $k < $inp_len; ++$k) {
			$v = ord($input{$k}); // Extract byte from input string

			if ($v < 128) { // We found an ASCII char - put into stirng as is
				$output[$out_len] = $v;
				++$out_len;
				if ('add' == $mode) {
					$this->_error('Conversion from UTF-8 to UCS-4 failed: malformed input at byte '.$k);
					return false;
				}
				continue;
			}
			if ('next' == $mode) { // Try to find the next start byte; determine the width of the Unicode char
				$start_byte = $v;
				$mode = 'add';
				$test = 'range';
				if ($v >> 5 == 6) { // &110xxxxx 10xxxxx
					$next_byte = 0; // Tells, how many times subsequent bitmasks must rotate 6bits to the left
					$v = ($v - 192) << 6;
				} elseif ($v >> 4 == 14) { // &1110xxxx 10xxxxxx 10xxxxxx
					$next_byte = 1;
					$v = ($v - 224) << 12;
				} elseif ($v >> 3 == 30) { // &11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
					$next_byte = 2;
					$v = ($v - 240) << 18;
				} elseif ($v >> 2 == 62) { // &111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
					$next_byte = 3;
					$v = ($v - 248) << 24;
				} elseif ($v >> 1 == 126) { // &1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
					$next_byte = 4;
					$v = ($v - 252) << 30;
				} else {
					$this->_error('This might be UTF-8, but I don\'t understand it at byte '.$k);
					return false;
				}
				if ('add' == $mode) {
					$output[$out_len] = (int) $v;
					++$out_len;
					continue;
				}
			}
			if ('add' == $mode) {
				if (!$this->_allow_overlong && $test == 'range') {
					$test = 'none';
					if (($v < 0xA0 && $start_byte == 0xE0) || ($v < 0x90 && $start_byte == 0xF0) || ($v > 0x8F && $start_byte == 0xF4)) {
						$this->_error('Bogus UTF-8 character detected (out of legal range) at byte '.$k);
						return false;
					}
				}
				if ($v >> 6 == 2) { // Bit mask must be 10xxxxxx
					$v = ($v - 128) << ($next_byte * 6);
					$output[($out_len - 1)] += $v;
					--$next_byte;
				} else {
					$this->_error('Conversion from UTF-8 to UCS-4 failed: malformed input at byte '.$k);
					return false;
				}
				if ($next_byte < 0) {
					$mode = 'next';
				}
			}
		} // for
		return $output;
	}

	/**
	 * Convert UCS-4 string into UTF-8 string
	 * See _utf8_to_ucs4() for details
	 * @access   private
	 */
	function _ucs4_to_utf8($input)
	{
		$output = '';
		$k = 0;
		foreach ($input as $v) {
			++$k;
			// $v = ord($v);
			if ($v < 128) { // 7bit are transferred literally
				$output .= chr($v);
			} elseif ($v < (1 << 11)) { // 2 bytes
				$output .= chr(192 + ($v >> 6)) . chr(128 + ($v & 63));
			} elseif ($v < (1 << 16)) { // 3 bytes
				$output .= chr(224 + ($v >> 12)) . chr(128 + (($v >> 6) & 63)) . chr(128 + ($v & 63));
			} elseif ($v < (1 << 21)) { // 4 bytes
				$output .= chr(240 + ($v >> 18)) . chr(128 + (($v >> 12) & 63))
						 . chr(128 + (($v >> 6) & 63)) . chr(128 + ($v & 63));
			} elseif ($v < (1 << 26)) { // 5 bytes
				$output .= chr(248 + ($v >> 24)) . chr(128 + (($v >> 18) & 63))
						 . chr(128 + (($v >> 12) & 63)) . chr(128 + (($v >> 6) & 63))
						 . chr(128 + ($v & 63));
			} elseif ($v < (1 << 31)) { // 6 bytes
				$output .= chr(252 + ($v >> 30)) . chr(128 + (($v >> 24) & 63))
						 . chr(128 + (($v >> 18) & 63)) . chr(128 + (($v >> 12) & 63))
						 . chr(128 + (($v >> 6) & 63)) . chr(128 + ($v & 63));
			} else {
				$this->_error('Conversion from UCS-4 to UTF-8 failed: malformed input at byte '.$k);
				return false;
			}
		}
		return $output;
	}

	/**
	  * Convert UCS-4 array into UCS-4 string
	  *
	  * @access   private
	  */
	function _ucs4_to_ucs4_string($input)
	{
		$output = '';
		// Take array values and split output to 4 bytes per value
		// The bit mask is 255, which reads &11111111
		foreach ($input as $v) {
			$output .= chr(($v >> 24) & 255).chr(($v >> 16) & 255).chr(($v >> 8) & 255).chr($v & 255);
		}
		return $output;
	}

	/**
	  * Convert UCS-4 strin into UCS-4 garray
	  *
	  * @access   private
	  */
	function _ucs4_string_to_ucs4($input)
	{
		$output = array();
		$inp_len = strlen($input);
		// Input length must be dividable by 4
		if ($inp_len % 4) {
			$this->_error('Input UCS4 string is broken');
			return false;
		}
		// Empty input - return empty output
		if (!$inp_len) return $output;
		for ($i = 0, $out_len = -1; $i < $inp_len; ++$i) {
			// Increment output position every 4 input bytes
			if (!($i % 4)) {
				$out_len++;
				$output[$out_len] = 0;
			}
			$output[$out_len] += ord($input{$i}) << (8 * (3 - ($i % 4) ) );
		}
		return $output;
	}
}

/**
* Adapter class for aligning the API of idna_convert with that of Net_IDNA
* @author  Matthias Sommerfeld <mso@phlylabs.de>
*/
class Net_IDNA_php4 extends idna_convert
{
	/**
	 * Sets a new option value. Available options and values:
	 * [encoding - Use either UTF-8, UCS4 as array or UCS4 as string as input ('utf8' for UTF-8,
	 *		 'ucs4_string' and 'ucs4_array' respectively for UCS4); The output is always UTF-8]
	 * [overlong - Unicode does not allow unnecessarily long encodings of chars,
	 *			 to allow this, set this parameter to true, else to false;
	 *			 default is false.]
	 * [strict - true: strict mode, good for registration purposes - Causes errors
	 *		   on failures; false: loose mode, ideal for "wildlife" applications
	 *		   by silently ignoring errors and returning the original input instead
	 *
	 * @param	mixed	 Parameter to set (string: single parameter; array of Parameter => Value pairs)
	 * @param	string	Value to use (if parameter 1 is a string)
	 * @return   boolean   true on success, false otherwise
	 * @access   public
	 */
	function setParams($option, $param = false)
	{
		return $this->IC->set_parameters($option, $param);
	}
}
?>